One body was left hanging from the bridge at the traffic circle where the National Highway meets Colosio Boulevard.

Four more bodies were found in a traffic lane on the bridge, and four on both sides of the boulevard, AG's office said.

“All (had) bullet wounds from gunshots to the head,” the office stated in a news release.

A Mexican federal source, speaking on the condition of anonymity, said a message was left with the bodies. But authorities did not disclose what it said.

An official with the public ministry said the nine dead men were between 25 and 50 years old, except for one, who was 16.

As of late Friday, none had been identified.

According to an investigation, the nine victims were at Table Dance, a club, when a fire broke out.

Firefighters responded to the blaze, but gun-wielding men kept them from fighting it.

“A squad of gunmen did not allow them to extinguish the fire,” the federal source said. “It wasn't until the gunmen left with the victims that the firefighters were able to work on (extinguishing the fire).”

On Wednesday, the U.S. Consulate in Nuevo Laredo warned Americans about an increase in violence related to what it called “transnational criminal organizations.”

The consulate urged those with no business in the city not to travel there.

In the warning, the embassy said there has been an increase in arson involving houses, as well as more attacks and killings.

The embassy said Los Zetas were competing with other cartels for control of Nuevo Laredo.

Friday's deaths come on the heels of the arrest this week of Jorge Costilla Sanchez, 41, the man who is alleged to lead the Gulf Cartel.

Costilla was arrested Wednesday night in the Mexican coastal city of Tampico by a platoon of Mexican marines. But he eventually might face justice in Houston.

He's wanted in Texas for drug trafficking, money laundering and his role in a November 1999 standoff in which an FBI agent and Drug Enforcement Administration agent were surrounded in Mexico and threatened at gunpoint with execution.

The Gulf Cartel has deteriorated significantly in the past few years, and Costilla's capture is seen as an opening for its rivals to take control of the prized Matamoros-Brownsville corridor for sneaking narcotics into the United States.

Questions remain now about what will happen to the remaining Gulf Cartel operations and what that will mean for violence in cities along Texas-Mexico border.